The present invention relates to a scheduling method for allocating a time and a job to each resource (person, installation), and more particularly to a job scheduling method suitable for a project which needs to consider a number of restrictions of the job allocation.
In order to complete a given project with limited resources (persons and installations), it is important to develop a schedule capable of allocating a suitable time and a suitable job to each resource. Without a proper schedule, jobs may concentrate on a particular resource or no job may be allocated to another particular resource thus leading to an inability to complete a workload per day.
Job scheduling has applications to various fields. One practical scheduling method is known described, for example, in "ACTIVITY NETWORK", by Elmagraphy, pp. 144 to 149, JOHN WILEY & SONS, March 1977. A brief description of a conventional system of this type will be given with reference to FIG. 2.
First, an earliest start time is allocated to each job (indicated by A to E in the Figure) to obtain an initial workload allocation result. In the example shown in FIG. 2, it is assumed that two persons are necessary for each job and the total number of persons is four. According to the initial workload allocation result, six persons are required at a peak workload, which means a shortage of two persons. With a conventional system, workload balancing has been carried out to balance the workload within a limited number of persons. Since a start time for each job is given an earliest start time at the initial workload allocation, there is a job or jobs which can be shifted to the right along the time axis, i.e., can be delayed. Therefore, a job (illustratively job F) which can be completed at the latest finish time is selected among the jobs and shifted to the right to the latest start time before the appointed time (time 20 in this example). Succeedingly, the similar procedure as above is repeated until the workload is balanced within the resource capacity.
The above conventional system, however, cannot be applied to various fields and is not suitable for the application to other than the manufacturing industry.